In the biotechnological industry, lysis kits are used to prepare biological material for analysis by turning the biological material into lysate. A lysis kit comprises a tube, a cap sealing the tube and a pipette tip for placing a sample of biological material into the tube and for withdrawing lysate from the tube. The tube may contain beads to help break the cells in the sample mechanically and to homogenise the disrupted cell material. The tube also contains a lysis buffer solution usually comprising a liquid reagent to help disintegrate the cells further without damaging the cell components to be analysed. The lysate is withdrawn from the tube by the pipette tip and transferred for analysis. The lysis kit has to satisfy a number of requirements which include:                The cap has to seal securely the lysis tube containing the lysis buffer solution and the beads        The pipette tip has to enter the lysis tube without the need to open the lysis tube or without the need to remove the cap        Easy piercing of the cap since the operator can apply only a limited force and secondly due to the fragility of the pipette tip used        The pipette tip should be easily removable from the lysis tube        Evaporation of the lysis buffer solution must be limited        The cap must provide good sealing during transportation/storage and during bead beating even if the cap has been pierced        Biological cross contamination must be avoided even if the cap has been pierced        The cap must be compatible with the pipette tip        
Also, the pipette tip has to be correctly positioned in the tube for dispensing the sample and to aspirate the lysate. Many solutions have been proposed so far to address the above requirements. However, a need still remains for improved pipette tip positioning in the tube in order to prevent undesired components of the lysate from entering the pipette during aspiration.
Accordingly, the object of the present invention is to provide a kit, a method and an assembly for preparing a sample of material which provide for improved pipette positioning in the tube compared to existing arrangements.